Current estimates put the number of cardiac catheritization procedures and interventions at over three million per year. Historically, such procedures were performed via the femoral artery. Since 1989, however, the number of cardiac procedures performed through the radial artery has increased significantly. The benefit of radial access lies in the potentially lower direct costs, patient preference, lower incidence of vascular complications (and their subsequent costs), as well as earlier ambulation. patients, the radial artery branches off of the brachial artery just below the level of the elbow crease. At this point, it passes on the lateral margin of the forearm until it reaches the level of the wrist. There are a significant number of patients (reported to be up to 12%) that may have an anatomic variant. The most common involves the radial artery originating just superior to the elbow, although in a few patients it may originate much higher in the arm.
In a typical cardiac intervention procedure through the radial artery, a sheath having a haemostatic valve is utilized to access a peripheral artery utilizing the administration of a local anesthetic at the vascular access site. A pre-shaped catheter is then introduced into the patient's vasculature through the sheath. The catheter can then be advanced to the ostium of the relevant coronary artery or to another desired location within the patient. The catheter enables delivery of medical instruments, medicines or fluids such as radiography contrast medium, angioplasty wires, balloons, and stents. During or after completion of the procedure, the sheath and catheter are removed and hemostasis can be achieved by manual compression, suturing the access site, or by utilizing another direct repair procedure.
The relatively superficial position of the distal radial artery enables relatively direct application of compression to the artery to achieve and maintain hemostasis during a procedure. Additionally the radial artery allows quick and direct closure at the catheter access site as soon as the arterial catheter has been removed at the end of the procedure.
As with any arterial puncture, achieving hemostasis during and/or after a procedure can be challenging. Typically the access site, or opening, in the artery is created utilizing a micropuncture apparatus, dilator or can even be formed utilizing a single straight incision to form a slit in the artery. The arterial walls include a layer of smooth muscle cells that expand and contract in conjunction with the rhythm of the heart to complement the pumping of the heart and to facilitate movement of blood throughout the body. The expanding and contracting of the radial artery may present challenges to achieving hemostasis at the access site. As a result of this and other factors, during the course of the procedure, blood may leak through the access site and around the outside diameter of the sheath or catheter. Existing radial artery compression devices are not adapted to provide desired and/or adjustable compression to the radial artery at the vascular access site during the course of a procedure.
When the procedure has been completed, typically the catheter is removed and the practitioner or medical professional will apply pressure at the vascular access site to achieve hemostasis and effectuate closure of the vascular access site. One technique for achieving hemostasis is to apply pressure at, or at a point slightly upstream, of the vascular access site. Typically, continuous pressure is necessary to stop bleeding and achieve hemostasis at the access site. While the applied pressure should remain relatively constant, there are advantages to applying a higher level of compression pressure at the beginning of the compression period and then reducing the level of compression pressure after a determined amount of time has elapsed. By gradually reducing the compression pressurization during the compression period, while continually maintaining at least a threshold level of compression, blood can begin to flow through the artery at a reduced pressure, providing nutrient rich blood to the tissue downstream from the access site. Blood flowing through the artery can then hasten clotting to enable hemostasis without application of ongoing compression. Not only can this provide improved closure, but also can improve the relative comfort of the patient.
Compression is typically applied to an access site by a nurse or other practitioner by manually holding a dressing at the access site. Although employing a practitioner to provide compression permits the gradual reduction of pressurization at the access site, it can also be a costly use of practitioner time. Alternative existing radial artery compression techniques which do not require the ongoing manual application of pressure by the practitioner may employ tape or a compression bandage at the vascular access site. These devices and techniques, while allowing the practitioner to attend to other matters, can render it difficult or impractical to adjust the compression pressure while maintaining continuous pressure. As a result, the tape or compression bandages may end up being positioned around the access site without being loosened or adjusted until they are removed.
Various types of automated manual solutions have been developed to, in part, address these issues. One example of an automated solution is shown by Petersen in U.S. Pat. No. 5,554,168. Petersen describes a free standing apparatus which may be attached to the bottom frame of a hospital bed. A pressure applying head is mounted on a swing arm attached to the vertical shaft of the base and can be positioned directly above the wound. Pressure is developed by either compressed air or an electric motor. Two pressure shoes can be positioned to provide both vertical and horizontal pressure.
Another automated solution is described by Lee in U.S. Pat. No. 5,133,734. Lee discloses a pneumatically operated femoral artery compressor applying calibrated and calibrateable external pressure on the puncture site of the femoral artery with the plunger end of a mounted pressurized assembly.
Breen et. al describes another type of partly automated solution, which also uses pneumatic pressure, in U.S. Pat. No. 5,792,173. Breen describes a wound closure device that includes an inflatable balloon with an inflation and deflation outlet. The balloon is coupled to patch, having an aperture for receiving the inflation/deflation outlet. The assembly is coupled to the placement patch and is held via a belt strap at either the wound site or on a bleeding vessel.
McNeese et al (US Pub. No. 2009/0281565) describes an even more complicated solution comprising a rotatable knob coupled to a threaded shaft and a pad. The screw can be tightened to provide pressure on the radial artery.
These automated compression devices are far from ideal, however. They tend to be expensive, difficult to maintain in good working order, consume a great deal of space and are difficult to keep sterile.
A number of manual compression devices have been described as well. Roth, in U.S. Pat. No. 5,263,965, describes a device that is used to apply direct pressure to arterial and venous incisions to promote hemostasis. It consists of a round flat disk with a user manipulable member used for applying downward pressure. In the preferred embodiment of the invention, the user manipulable member consists of a peg over which a cylindrical weight is pivotally mounted. A stretchable bandage is used to secure the weight in place.
Another type of manual compression device is described by Toller in U.S. Pat. No. 5,342,388. This manual compression aid is comprised of a cylindrically shaped handle above a sterile disposable disk. The disk is placed above the catheter insertion point with the catheter inside the notch of the disk. As the catheter is removed, pressure is applied to the handle to force the disk to compress the artery and thereby control bleeding—ultimately achieving hemostasis. This type of device has a number of disadvantages including: the cost of the apparatus; the difficulty associated in ensuring a minimal level of cleanliness; and the time associated in connecting the disposable disk to the assembly prior to its use on a patient.
Benz et. al describe another form of manual compression device in Pub No. US 2003/0028214. This manual vascular compression device also includes a handle an elongated shaft and a pad or disk. In this device the pad or disk is integral to the assembly and the entire apparatus is disposable. Like the pad of Toiler, the pad is flat and contains a notched or equivalent area for locating the catheter.
These, as well as currently commercially available hemostatic control devices such as the Radistop (RADI, Uppsala, Sweden), and the TR Band (Terumo, Japan) have been moderately effective in helping to achieve hemostasis in radial artery interventions and have established the standard of care at between 2-6 hours post-procedure to achieve hemostasis, as well as having significant potential for re-bleeding. These relatively long latencies in achieving result in increased patient discomfort as well significant healthcare (e.g., nursing and monitoring) resources being devoted to patients. What is therefore needed is a more efficient system for achieving radial artery hemostasis more quickly and efficiently and with a reduced potential for re-bleeding.